Gate Drive On Array (GOA) technology is a driving mode, in which gate drives are disposed on a thin film transistor (TFT) array substrate by means of a process for manufacturing a thin film transistor array so as to achieve driving row by row.
Since the GOA technology is beneficial for design of a narrow bezel on a gate drive side of a display screen and a reduction of cost, it is widely applied and researched.
With the development of oxide semiconductor thin film transistors (for example, indium gallium zinc oxide (IGZO) thin film transistors), integrated circuits which are on the periphery of a panel with an oxide semiconductor become a focus of attention. Since carrier mobility of oxide thin film transistors is 20 to 30 times of carrier mobility of amorphous silicon thin film transistors, charge and discharge rates of the thin film transistor to pixel electrodes can be greatly increased. As can be seen, the oxide thin film transistor can increase a response speed of pixels and achieve a faster refresh rate, so that the row scan rate of the pixels can be greatly increased and an ultra high resolution in a TFT-LCD becomes possible. A GOA circuit of the oxide semiconductor thin film transistors may replace a GOA circuit of the amorphous silicon thin film transistors in the future.
However, there is little development on the GOA circuit of the oxide semiconductor thin film transistors in the prior art, because many problems caused by electrical properties per se of the oxide thin film transistors need to be overcome. Specifically, since IGZO is an N-type semiconductor and does not have many holes, an IGZO-TFT generally exhibits a better negative bias temperature stress (NBTS) property. However, a positive bias temperature stress (PBTS) of the IGZO-TFT is unsatisfactory. A long-time positive bias temperature stress will cause a positive drift of a voltage threshold (Vth) of the TFT, so that a speed for turning on an IGZO-TFT device becomes slow, which further has a serious influence on the GOA circuit.